Combined musical instrument



vSe t. 4, 1956 J. A. KQEHL 2,761,344

COMBINED MUSICAL INSTRUMENT Filed April 15, 1953 5 Sheets-Sheet 1 Sept.4, 1956 J. A. KOEHL 2,761,344

COMBINED MUSICAL INSTRUMENT Filed April 15, 1955 5 Sheets-Sheet 2 EllSept. 4, 1956 J. A. KOEHL COMBINED MUSICAL INSTRUMENT 5 Sheets-Sheet 3Filed April 15, 1953 SepI. 4, 1956 J. A. KOEHL COMBINED MUSICALINSTRUMENT 5 Sheets-Sheet 4 Filed April 15, 1953 Sept. 4, 1956 FiledApril 15, 1953 J. A. KOEH 5 Sheets-Sheet 5 UPPER KEYBOflRdWF/ZHES LOWERlrs )EOHRDJWITGHES -J '?7 I A/ OUHLITV l P awn [Ty CONTROL corvrnoz.

F J, IIMPLIFIER ZZ'ZZ Z E E1 [3 g L TONE Gf/VffiflTOfifi /I v z? Paw/uCLRVIER V United States Patent COMBINED MUSICAL IN STRUlVIENT James A.Koehl, Evanston, 11]., assignor to Central Commercial Industries, Inc.,Cook County, 111., a corporation of Illinois Application April 15, 1953,Serial No. 348,915

3 Claims. (Cl. 84171) This invention relates to musical instruments andmore particularly to an instrument for the playing of both percussiveand sustained tones and whereby either of these types of tones can beproduced separately or together for versatile musical eifects.

An essential object of the invention is the provision of an organizationof elements providing a composite instrument in which use is made of apiano having a conventional action operated from the instrumentskeyboard for the playing of piano music in the customary manner andmeans including a removable section of the case of the piano forsupporting a keyboard in playing relation to the keyboard of the pianoso that and by coaction of both keyboards with an electrical tonegenerating and translating system the combined or composite instrumentcan be played in a manner typical of a dual manual type, reed orelectric organ.

A further object of the invention is the provision of a combined pianoand electric organ in which an extra keyboard is embodied in the case ofthe piano to provide a dual keyboard in playing relation to the keyboardof the piano without necessitating any change in the elevation of thelatter from the floor.

A still further object of the invention is the provision of anorganization of elements including a removable section of the case of apiano, which section supports a keyboard and a system of tone controls,in a manner enabling said section and all of its supported elements tobe readily applied to and removed from the case of the piano as aunitary structure and whereby both of the aforementioned keyboards willbe related to each ,other for playing thereof the same as is customarywith a conventional two-manual organ.

Another object is the provision of means for use with a piano for theproduction of electrically generated sustained tones of any selectedtimbre and whereby the key ing switches employed in the organization areseparable from a tone signal transmitting mechanism in a manner enablingconvenient removal of said detachable section of the case and subsequentconnection of the keying switches in said network when reattaching saidsection to the case.

A still further object is the provision of a dual set of electric keyingswitches which are formed, constructed and adapted for convenientinstallation in the case of a piano and so that accessibility is hadthereto for the purpose of adjustment, cleaning and repair of theswitches.

Another object of the invention is the provision of a unique combinationof elements, which, when installed in a piano will give to theinstrument a pleasing effect and function in the system in a mannermaking for ease and convenience in playing.

Other objects and advantages of the invention will be pointed to in thefollowing description and disclosed in the accompanying drawings, inwhich:

Figure 1 is a perspective view of the combined instrument;

Figure 2 is a vertical transverse section through a por- Patented Sept.4, 1956 'tion of the instrument taken in the boards;

Figure 3 is a perspective view of the front section of the case of thepiano with its supported keyboards and quality control;

Figure 4 is a detailed section in plan view showing the manner ofmaintaining a fixed relation of the keyboard to the conventionalkeyboard of a piano;

Figure 5 is a sectional detail perspective view of one of the keyassemblies;

Figure 6 is a schematic view of an electrical network show-ing theinvention connected therein;

Figure 7 is a view similar to Figure 2 showing a slight- 1y modifiedform of the invention; and

Figure 8 is a schematic view of the two keyboards to make clear therelationship to each other of the white and black keys of like noteletter and pitch.

At Figure 1 is shown the complete instrument and in Figure 2 of theaccompanying drawings are upper and lower keyboards to be describedhereinafter in detail. Underneath all keys of the upper keyboard andunderneath at least certain keys of the lower keyboard are similarelectric switches 20, such that the individual switches are selectivelyactuable according as pressure is plane of both key- 1 applied to andremoved from said keys.

At Figure 6 is a schematic illustration of an electrical networkincluding a system of electrical tone generators A, a pedal clavier B,an audio amplifier C having a loudspeaker D in its output circuit, avolume control device E, quality controls F and G, a set of electricswitches H for the upper keyboard and a similar set of electric switchesI for the conventional keyboard of the piano.

From the generators A are cables I and K detachably coup-led at J and Kto the switches of the respective sets of switches H and I. Each ofthese cables will consist of as many leads as there are switches in anyset of said switches. Generators A will comprise a number of individualaudio frequency generating devices suflicient to supply all switches ofa keyboard with signal voltages in the pitch relation to notesassociated with the keys thereof.

At L and M are cables connecting the switches of the respective sets ofswitches to the respective quality controls F and G, the cable Mincluding a separable coupling N for disconnecting said cable fromquality control F. From the quality controls P and G are outputconductors O and P connected :to the input circuit of amplifier C byseparable couplings Q and R.

'The pedal clavier B connects to the amplifier C via lead S and to thegenerators A via lead T.

It is intended that output tone signals from said generators A shall beavailable as desired when playing one or both keyboards of the hereindisclosed instrument. It sufficies to say that signal voltage will betransmitted to a respective quality control F or G and then to amplifierC for activation of loudspeaker D. The purpose of couplings K, J, N, Q,and R is to enable disconnecting the switches H and the quality ofcontrols F and G from other parts of the electrical network, as parts ofa removable section of a piano as will be more fully pointed to in thefollowing description.

At Figure l the case U of the piano U has upper and lower keyboardsdisposed in superposed parallel relation to each other, the upperkeyboard carried by a removable front section W of said case.

The approximate dimensional size of the case U is as follows:

Elevation of .the lower surface of the bed plank V above the floor, 24";Elevation of the upper surfaces of the white keys of the upper keyboardabove the playing surfaces of the white keys of the lower keyboard, 2/2;

Length of the elfective playing surfaces of the white keys of the upperkeyboard 5 /2, the same as the effective playing surfaces of the whitekeys of the piano keyboard;

Distance from front of back check of action to the inner face of thevertical portion W of the removable front section W of case, between oneand two inches.

The action and other instrumentalities of the piano may be of anywell-known construction. When the front section of the case is removed,free access is had to the tuning pins of the piano.

In carrying the invention into practice, use is made of any well-knowntone signal generators such as those shown in the Larsen Patent No.2,403,090. The invention is primarily designed, adapted and intended foruse in a system in which the tone signal generators are mounted on theinner face of the kneeboard Z of the piano, upon which the loudspeakeris also mounted so as to project sound in a forward direction. Such anarrangement is disclosed in the Patent No. 2,649,007 to Walter J.Anderson. The main feature, however, is the embodiment in a piano of asecond keyboard above the conventional keyboard, the latter and theformer having respective key switch assemblies associated therewith forthe transmission of signal voltages to an electroacoustical translatingsystem when playing said keyboards.

Figure 1 of the accompanying drawings discloses the general features ofthe invention and embodiment thereof in the case of a piano whose bedplank and keyboard are at the accepted or customary elevations abov thefloor. At Figure 2 the bed plank V of the case of the piano is providedat its front end with the customary key slip 10. The conventional keys11 of the keyboard of the piano are carried by a mounting 12 whichincludes a fulcrum or balance rail 13 for the keys and front guide pins14. The keys 11 extend under a removable stop strip 15 and their upwardpivotal movement is stopped and cushioned by felt 16 on the lowersurface of the strip. At the back of the strip is a longitudinal shell17 positioned at an elevation to dispose a key mounting 18 in a positionto support the playing-keys 19 of the upper manual 20 at an elevation tobring the keyboard of the piano and said keyboard 20 within the span ofthe hand. In practice, the vertical distance separating the back ends ofthe effective playing surfaces of the white keys of the piano keyboardand the front ends of the effective playing surfaces of the white keysof the keyboard 20 is about 2 /2". The keys 19 of the keyboard 20project underneath the felt faced lower edge of the vertical portion Wof the section W of the case of the piano. Said vertical portion W issecured to a horizontal section 21 which, with the longitudinal strip 22provides a music rest and from the back edge of the horizontal portion21 is an upwardly and rearwardly flared portion 23. The flared section23 of the removable section W of the case of the piano extends to thetop of the case as shown at Figure 1. It is also co-extensive with theeffective length of the piano inside the ends of the case. The mounting18 is provided with devices 24 and 24' which coact with devices 25' and26' on the white and black keys of keyboard 20 to limit upward pivotalmotion of said keys. The back edge of said mounting has detachablysecured thereto a longitudinal strip 25 having a longitudinal row ofequi-distantly related flat leaf springs 26, the upper ends of which aresecured at 27 to the respective keys so that the springs function toresiliently support the keys, and hinge-like enable the keys to bedepressed when playing pressure is applied thereto.

The keyboard support 18 has a length substantially coextensive with thatof the removable front section W of the case of the piano as clearlyshown at Figure 3. At the respective ends of the keyboard 20 are stopcontrols 31 and 32, each provided with a number of pivoted switchcontrolling tablets 33. Laterally of these controls are wood blocks 34which are in stepped relation to the cheeks 35 at the respective ends ofthe keyboard of the piano.

The controls 31 and 32 may be hollow box-like structures of plastic orany other suitable well-known material. At the respective ends of theflared portion 23 of the removable section W of the case U are strips ofwood 35 and at the base of the section are angle brackets 35' whichextend under and are secured to the bottom surface of the keyboardsupport 18. To these brackets and also secured to the inner face of thevertical portion of the section W are depending supporting legs 36,preferably of metal, eaoh provided at its lower end with a horizontalflat foot 37 the under surface of which is preferably felted as at 38.

The construction disclosed in Figures 2 and 3 is such that the section Wof the case of the piano may be removed by pulling same upward when thecover of the piano is opened. The legs 36 are narrow and such that theirfoot portions 37 rest upon the upper surface of the bed plank V justoutside the extreme end keys of the keyboard of the piano. When thesection W is thus disposed the upper edge of the flared portion 23 comesimmediately in line with the under surface of the cover of the piano.The end strips 35 extend into the case immediately adjacent to the innerfaces of the ends thereof and forwardly of the plate of the piano asshown at Figure 4. Wedges 39 are then inserted between the front of theplate and said strips 35 so as to force the forward edge of the keyboardsupport 18 against the stop 17. This provides a rugged construction thatprevents any of the parts of the device from rattling when the piano isplayed.

The quality controls 31 and 32 may comprise any well-known system ofWave filters and coacting electric switches, the latter actuable by saidtablets 33. The system disclosed in said Larsen patent is satisfactoryfor the general purpose of the invention but shall not be construed aslimiting the invention to use of such device.

Upon referring to Figures 2 and 5 of the drawings, it is noted thatunderneath the respective keyboards are sets of electric switches 20'such that for each separable key there is an electric switch actuablethereby to closecircuited conditioning when the key is depressed and toa circuit breaking condition when the key is at the uppermost limit ofits pivotal motion. I have previously pointed to the method ofconnecting the separate sets of switches in an electrical tonegenerating and translating network and it need only be mentioned thatthe switches are such that they can be easily mounted under therespective keyboards for coaction with the keys thereof.

Should it be desired to remove the front section W of the case of thepiano, it is only necessary to disconnect the key switch assembly ofkeyboard 20 from the network as provided for by means of the couplingsN, K, Q and R and then remove the wedges 39 and lift the front sectionfrom the case.

All circuit connections to the quality controls may be made from in backof the removable section W of the case when the cover of th case isopened. When strip 25 with its springs 26 is removed the keys 19 may belifted from the mounting 18, thus to expose the switch assemblyunderneath the keys.

In the form of the invention shown at Figure 7 a horizontal key mounting40 is carried by the vertical portion 41 of the removable section W ofthe case of the piano, the arrangement being the same as described inthe aforementioned first embodiment of the invention. The forwardportion of said mounting rests upon a stop strip 42 which limits theupward movement of the keys 43 of the keyboard of the piano, and saidstrip may be detachably attached to the case of the piano in anywell-known manner. The support 40 is provided with a key slip 44 havinga stop flange 45 which coacts with a lug 46 on the bottom side of eachkey of a keyboard 47. Guide pins 48 project upwardly from the support 40and are coactive with the keys of said keyboard to guide them in theirmovement. The keys in this embodiment of my invention are of shorterlength than the keys in the first referred to embodiment and asillustrated they are organ-type keys in which the front ends of thewhite keys project into the vertical plane of the keyboard of the piano.The overhang is about 1 /2" of the total length of the white keys of thepiano keyboard and the distance between the upper playing surfaces ofthe keys of this keyboard and the upper surfaces of the white keys ofthe piano keyboard is about 2 /2 measured from a line close to the backends of the effective playing surfaces of the white keys of said pianokeyboard. Attached to the back edge of the support 40 is a strip 50having a longitudinal row of equi-distantly spaced-apart fiat leafsprings 51, the upper ends of which are secured at 52 to the back endsof the keys. Each key is also provided with a switch actuator 53 whichextends upwardly and is so related to switch contactor 54 that when akey is depressed the actuator will move the contactor 54 into circuitmaking connection with switch contactor 55. Contactor 54 is adapted tobe connected to a source of signal voltage and contactor 55 may beconnected to a signal output bus-bar, not shown. As first above stated,the keys in this type of keyboard are shorter than the keys of theconventional piano keyboard but by projecting the back ends of the keysa slight distance through the vertical portion 41 of the removablesection W of the case, and mounting same, as shown, the effectiveplaying surfaces of the white keys may be about 4".

Also in the embodiment shown at Figure 7, I preferably mount under eachof the keys, a block of very yieldable sponge or foam rubber 55'. Foreach of these blocks is a vertically adjustable presser 56 having ascrew 57 which is exposed from the underside of the mounting 40 so thatthe upper end of the screw will move pressing element 58 against theunderside of a respective block 55, thereby displacing the rubbersufficiently to control the amount of pressure applied to a key todepress same. It is understood that the back ends of the keys passthrough a longitudinal slot 59 in the vertical portion 41 of theremovable section W of the case, and, as shown, the upper wall of thisslot is faced with felt 59'. As in the first embodiment of my invention,this modified form may be applied to the case of the piano and removedtherefrom with the keyboard as a unitary structure.

It is understood that the upper keyboard of the invention will generallyconsist of about 60 keys and that they will be aligned with keys of likenote letter and pitch of the piano keyboard. It is also understood thatthe tone generators will consist of a number of individual generators,generally not less than sixty and that they will produce output tonesignals for a scale tuned in equal temperament. Each individualgenerator may concurrently serve both keyboards of the instrument andalso the keys of the pedal clavier, the latter connected in the circuitas set forth in the description of Figure 6 of the accompanyingdrawings.

The switches underneath the playing-keys 11 of the keyboard of the pianoand switches 20' underneath the keys of keyboard 20 consist of similarassemblies of switches, the switches for the keys of said keyboard 20being contained in the space between the underside of the keys and theupper surface of the mounting 18. The switches 20 for the keys of thepiano keyboard are similarly supported by the aforementioned mounting12, all as shown at Figure 2.

While any well known type of electric switch may be combined with saidkeyboards, I have shown a switch which is satisfactory for the purposeof my invention. Each separate assembly of switches will consist of aflat longitudinal strip 643 of hard insulating material provided with abus-bar 61 with which the resilient longitudinally spaced apartcontactors 61a are engageable when their associated playing-keys aredepressed. These contactors extend underneath a strip of hard insulatingmaterial 62 secured at 63 to strip 60 and having terminals 64 exposed,as shown, from one edge of said strip 60 for attachment thereto of atone signal conducting lead 65. Attached to said strip 62 are resilientactuators 66, such that there is one such actuator for each of thecontactors 61a. Each actuator has an upwardly curved portion 67 hearingwith only light pressure against the underside of a respectiveplaying-key, and, as shown, said portion 67 has a free end 63 which isspaced apart from the free end 69 of coacting contactor 61a when the keyis at the uppermost limit of its pivotal motion and is adapted to engagesaid contactor and advance same into circuit completing engagement withsaid bus-bar 61 when the key is depressed. The lead wires 65 of thesecontactors are formed into cables such as those schematically shown at Kand I at Figure 6. Thus, it can be assumed that leads L and M at Figure6 are bus-bars for conducting tone signal voltages to the respectivequality controls P and G.

The tone generators A, amplifier C and loudspeaker D are preferably butnot necessarily mounted inside the case U and upon the kneeboard Z. Iprefer this arrangement in that all parts of the invention areself-contained in a common case, thus to provide a two-manual electricorgan combined with a conventional vertical piano, all within a space nolarger than that required to accommedate a vertical piano of averagesize, and whereby the instrument can be readily moved from place toplace with ease and convenience.

In each of the herein disclosed embodiments of my invention, use is madeof a conventional piano to provide a combined instrument characterizedby an upper short keyboard mounted on a detachable section of the caseof the piano and the customary keyboard of the piano, such that whensaid detachable section is applied to the case, both keyboards will bein stepped relation to each other. It follows that if the upper keyboardhas, say, 60 playingkeys, a like number of playing-keys of an 88 notepiano keyboard constitutes therewith a system of keys enabling theinstrument to be played in a manner typical of a twomanual organ. Iaccordingly stress the unique and novel arrangement of the hereindisclosed parts.

At Figure 8 of the drawings there is schematically shown a pianokeyboard having 88 notes and a short keyboard having 60 playing-keys,the latter providing a tonal range of five octaves. The figureillustrates clearly that the bottom key of the short key bearing thenote letter (C: 65.41 C. P. S.) is in line with key O of the samevibration frequency of the piano keyboard. Similarly, the last key inthe upper register of the short keyboard, namely B=l975.53 C. P. S. isaligned with key B of the same tone frequency.

What I claim as my invention is:

1. A musical instrument comprising a case having therein tuned vibratileelements for producing audible sounds in the pitch relation to thevibration frequencies of notes of the chromatic scale; a keyboardextending forwardly from the case; an action actuable by the keys ofsaid keyboard and coactive with said vibratile elements for placing samein audible vibration; said case having a substantially verticallydisposed front member provided with a forwardly extending keyboardmounting having thereon a keyboard, the dimensional size and the shapeof said member being such that when the member is applied to the casethe second named keyboard is disposed above and in stepped relation tothe first named keyboard; means rigidly securing said member to and forenabling removal thereof from the case; generators respectivelyproducing output tone signals in the aforementioned pitch relation; setsof electric switches for and actuable by the playing-keys of therespective keyboards; an electroacoustical translating system; and anelectrical network in which the switches of said sets of switches, thesaid generators and the translating system are connected for activationof said system according as one or both of said keyboards are played,the set of electric switches common to the second named keyboard beingseparable from said network enabling removal as desired of theaforementioned member from the case together with the second namedkeyboard and the set of switches common thereto as a unitary structure.

2. An organization of elements adapted for use in combination with avertical piano of the class embodying a case having a bed plank, akeyboard mounted on said bed plank, a hammer action actuable from saidkeyboard, and tuned strings coactive with said action and adapted to beselectively vibrated to produce audible percussive sounds when playingsaid keyboard; said mechanism comprising a member adapted to beremovably fitted to said case between the top thereof and said keyboardand serving when removed to expose the interior of the case above saidkeyboard and when applied to the case to close the front thereof abovesaid keyboard; a keyboard carried by said member and disposed in steppedplaying relation to the keyboard of the piano; and means for producingsustained organ-like tones when playing one or both of said keyboards,said means comprising a system of tone generators respectively producingwaveforms of audio signals at the tone frequencies of notes of the scaleassociated with different keys of said keyboards, means for translatingsaid signals into audible sounds, sets of electric switches coactivewith the keys of the respective keyboards and said sustainedtone-producing means for rendering said generators effective foractivation of the translating means, one of said sets of switches beingsupported by said removable member and having separable connection withsaid sustained tone-producing means enabling removal of the second namedkeyboard from and application of same to the case as a unitary part ofsaid member.

3. An organization according to claim 1 wherein the removable member isprovided with legs freely resting on said bed plank and wherein meanscoactive with the case and said member are provided for securing themember against vibration.

References Cited in the file of this patent UNITED STATES PATENTS 64,371Rox Apr. 30, 1867 308,415 Kuster NOV. 25, 1884 1,092,291 Robinson Apr.7, 1914 1,169,654 Knabe Ian. 25, 1916 1,196,401 Severy et a1 Aug. 29,1916 1,561,100 Mills Nov. 10, 1925 1,622,364 Barbieri Mar. 29, 19271,623,211 Starkie Apr. 5, 1927 2,250,065 Koehl July 22, 1941 2,471,534Muth et al. May 31, 1949 2,555,040 Jordan May 29, 1951 FOREIGN PATENTS17,128 Great Britain of 1914

